Tree Improvement Program Project Report 2006 / 2007

.2.17 Development of Yellow-Cedar
Stock Plant Nutr t on Gu del nes
to Enhance Operat onal
Root ng of El te Clones
(SPU 111 )
Robert van den Dr essche
Yellow-cedar reforestation in BC is almost entirely through
clonal forestry using rooted cuttings. For example, the
Ministry of Forests and Range Cowichan Lake Research
Station grows stock plants chosen from selected yellowcedar.
These yellow-cedar plants have been selected because
they have shown superior growth in the forest and also
good ability to root from cuttings. The stock plants are
grown outdoors, either in pots or field-planted, and are
kept small by pruning because pruning, or “hedging,” tends
to slow the aging process. Slowing aging and maintaining
juvenility is important for producing cuttings that grow like
seedlings. That is, they root easily and have vigorous shoot
growth. Research studies at CLRS have shown that serial
propagation by using a proportion of each generation of
rooted cuttings as hedges for the next generation conserves
juvenility for about 15 years.
Recent operational experience indicates the potential
benefit of growing stock plants in greenhouses for
increasing the rooting of cuttings. This benefit may, in part,
be attributed to a more optimal nutrient status for rooting
ability among stock plants. Little is known about the effect
of yellow-cedar stock plant nutrition on the rooting ability
of cuttings, although nutrition is relatively easy to control
and stock plant nutrition has been shown to influence the
performance of cuttings in plants.
In particular, the balance between concentrations of
total non-structural carbohydrates and nitrogen has been
thought important for rooting, although the relationship of
cutting performance to several nutrients has been reported.
Additionally, production by the WFP Saanich nursery of
yellow-cedar cuttings that rooted and grew vigorously was
attributed to adding fertilizer to the stock plants during the
fall. Consequently, we decided to study the importance of
nitrogen and phosphorus, and the time of their application,
to potted stock plants of different clones and ages at
the CLRS. The objective is to relate different levels of
nutrient status in stock plants, achieved with the fertilizer
treatments, to subsequent rooting and growth vigour of
cuttings. It should then be possible to recommend levels
T R E E I M P R O V E M E N T P R O G R A M
P R O J E C T R E P O R T 2 0 0 6 / 2 0 0 7
of stock plant nutrient status for the successful production
of cuttings. So far, a small-scale experiment has produced
cuttings that have been struck this winter, and samples
of these cuttings are undergoing chemical analysis. Also
plant material has been potted and prepared for a larger
experiment that will be conducted during 2007 and 2008.
.2.1 Fert l ty Var at on n a Douglasfir
Seed Orchard as Determ ned
by DNA F ngerpr nt ng: an
Update
Ben La , Annette Van N ejenhu s, and
Yousry A. El-Kassaby
Because seed orchards represent the main sources of
genetically improved seed for most artificially regenerated
forests, they play an important interface role between tree
breeding and silvicultural activities. The production of seed
crops with high genetic quality (gain and diversity) in all
BC orchards is critical to the success of tree improvement
programs and to meeting the genetic quality required under
the Chief Forester’s Standards for Seed (2005).
This project is part of a larger initiative started by the
BC Ministry of Forests and Range, the forest industry,
and academia aimed at obtaining accurate estimates of the
genetic quality of seedlots. Genetic quality is defined as the
level of genetic gain combined with the degree of genetic
diversity. Orchard managers routinely assess these estimates,
and estimates such as genetic worth (GW) and effective
population size (N e ) are an integral part of the evaluation of
seed-orchard crops.
DNA fingerprinting technology coupled with methods
of pedigree reconstruction will be used to obtain accurate
estimates of the genetic contribution to a specific seedlot
of each parent in Western Forest Products’ Douglas-fir seed
orchard. These estimates will be compared with survey
assessment methods that are based on visual inspection
of trees’ reproductive output. Additionally, the use of
DNA technology will permit the estimation of pollen
contamination from outside sources and the effectiveness of
orchard management practices such as supplemental mass
pollination (SMP) and over-head cooling (bloom delay).
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